A. A. Saeed, et al.: Neutron Shielding Prop erties of a Borat ed High-Density ... 120 Nuclea r Technol ogy & Ra dia tion Pro tection: Year 2017, Vol. 32, No. 2, pp. 120-126

NEUTRON SHIELDING PROP ER TIES OF A BOR ATED HIGH-DENSITY GLASS

by

Aly Abdallah SAEED 1, Raed Mohamed El SHAZLY 2, Mohamed Mahmoud El-OKR 2, Ali Moheeb Abou El-AZM 2, Yahia Hamdy ELBASHAR 3*, Mohamed Nasef Hassan COMSAN 4, Wagdy Ahmed KANSOUH 4, and Ahmed Reda EL-SERSY 5

1 Nu clear Power Sta tions De part ment, Fac ulty of En gi neer ing, Egyp tian-Rus sian Uni ver sity, Cairo, Egypt 2 Phys ics De part ment, Fac ulty of Sci ence, Al-Azhar Uni ver sity, Cairo, Egypt 3 De part ment of Phys ics, Fac ulty of Sci ence, Aswan Uni ver sity, Aswan, Egypt 4 Nu clear Re search Cen ter, Egyp tian Atomic En ergy Au thor ity, Cairo, Egypt 5 Na tional In sti tute for Stan dards, Cairo, Egypt

Sci en tific pa per http://doi.org/10.2298/NTRP1702120S

The neu tron shield ing prop er ties of a bo rated high den sity glass sys tem was char ac ter ized ex - per i men tally. The to tal removal mac ro scopic cross-sec tion of fast neu trons, slow neu trons as well as the lin ear at ten u a tion co ef fi cient of to tal gamma rays, pri mary in ad di tion to sec ond - ary, were mea sured ex per i men tally un der good geo met ric con di tion to char ac ter ize the at ten -

u a tion prop er ties of (75-x) B2O3-1Li2O-5MgO-5ZnO-14Na2O-xBaO glassy sys tem. Slabs of dif fer ent thick nesses from the in ves ti gated glass sys tem were ex posed to a collimated beam of neu trons emit ted from 252Cf and 241Am-Be neu tron sources in or der to mea sure the at ten u - a tion prop er ties of fast and slow neu trons as well as to tal gamma rays. Result s con firmed that bar ium bo rate glass was suit able for prac ti cal use in the field of ra di a tion shield ing. Key words: shield ing mate rial, fast neu tron, slow neu tron, re moval cross-section, gamma ray

IN TRO DUC TION portant is to moder ate the neutron to low ener gies, where neu tron can readily be cap tured in mate ri als Ion iz ing ra di a tion has harm ful ef fects on hu man with high absorp ti on cross sec tion [8, 9]. The most ef - health and en viron ment., The same appli es to nu clear fec tive mod er ators are el em ents with low atomic num- technol o gi es acc ompa nie d with seve ral haza rdous sit - ber; and there fore hy dro gen con tain ing ma te ri als are u ati ons for liv ing or ganism s. Therefore, it was neces - the major ef ficie nt com ponents of most neutron sary to develop technol o gies for pro tecting against nu - shields, such as wa ter and par af fin. How ever, wa ter clear ra di ation [1, 2]. Hence, the shield ing mate rial shields have the disad van tage of needing mainte - against nu clear ra di ation was born and at tracted a nance; also, evapo ra ti on can lead to a poten ti ally dan - great deal of at tenti on [3, 4]. The most im portant radi a - ger ous loss of shield ing ef fec tive ness, while par af fin tions in the field of pro tec tive mate ri als are neu trons is flam mable. If the neutron ener gy is suf ficie ntly and gamma-rays be cause they are the most pen etrat ing high, in elas tic scat ter ing with heavy nu clei can take for dif fer ent ma te ri als [5]. The ef fec tive ness of shield - place in which the recoil nucle us is ele vate d to one of ing var ies with the type and ener gy of ra dia ti on and its excit ed states during the col li sion. The nucle us also accord ing to the de sired purpose of the shielding quickly de-ex cites; emitting a gamma ray, and the neu - [6]. Of ten a com bi na tion of three ma te ri als is de sir able tron loses a greater frac tion of its ener gy than it would that in cludes heavy ma te ri als, light ma te ri als, and neu - in an equiv a lent elas tic col li sion [10-12]. In elas tic tron-absorb ing mate ri als to omit the slow neutrons scatter ing and the subse quent gamma ray emission through absorp ti on of the neutron shield [7]. The play an im portant role in the shielding of high-ener gy shield ing of neu trons in tro duces many com pli ca tions neu trons. Ma te ri als with good in elas tic scat ter ing becaus e of a wide range of the ener gy that must be con- prop er ties are the heavy ele m ents, such as iron and sidered and the second ary produc ti on of gamma rays. lead, which used to offset this de crease in cross sec tion To choose neutron shielding mate ri als , the most im - with increa sed neutron ener gy [13]. These mate ri als can cause a large change in neu tron en ergy af ter col li- * Cor re spond ing au thor; e-mail: y_elbashar@ya hoo.com A. A. Saeed, et al.: Neutron Shielding Proper ties of a Borat ed High-Density .. Nuclea r Technol ogy & Ra dia tion Pro tection: Year 2017, Vol. 32, No. 2, pp. 120-126 121 sion for high-ener gy neutrons, while they have a lit tle ef fect on the neutrons at lower ener gy, below 0.1 MeV [14, 15]. The 10B is ef fec tive for ab sorb ing epi ther mal neutrons (ener gy range 0.1 eV to 10 eV), and was in- cluded as a neutron absorber in vari ous mate ri als , e. g. borat ed graphit e, boron carbide, Boral, and boron ox- ide [16, 17]. Present work was focuse d on the study of im - pregna ti on of boron oxide in the glassy sam ples in ad- diti on to a study on the influ ence of barium in the form Fig ure 2. Ex per i men tal lay out of BaO (r = 5.73 gcm–3) on the att enu a t ion proper t ies of slow and fast neutrons as well as the total gamma crim i na tion ca pa bil ity. The neu tron-gamma crys tal rays. or ganic scin til la tion spec trom e ter with stilbene scintillator of di mension 4 cm ´ 4 cm was used to mea- sure the recoil proton and elec tron pulse am pli tude dis- SAM PLES PREP A RA TION tri bu tions. Ex per i men tal lay out of the mea sur ing sys - tem was pre sented in fig. (2). Fast neutron and total Pure, com mer cially avail able, raw ma te ri als gamma ray fluxes transm it ted through dif ferent barri - were used to pre pare a glassy system of the com pos ite ers of glass sam ples under inves ti gati on were used to (75-x).B2O3-1Li2O-5MgO-5ZnO-14Na2O-xBaO per form the at ten u a tion prop er ties of such glass, (where x = 0, 10, 20, 30, 40, and 50 mol %) by the where the shielding param eter s of fast neutrons and to- melt-quenching technique with dim ensions 4 cm ´ 4 tal gamma rays were ob tained. cm and dif ferent thicknesse s (0.6 cm-1.02 cm). The dry powders were mixed, hom oge nize d and then melted at a tem pera ture of 1000 °C for 4 hours in por- Slow neu tron mea sure ments ce lain cru ci bles. Once a ho mo ge neous free bub ble liq - uid was obtai ned, it was poured into a stainles s steel A collimated beam of neutrons emit ted from mold and then anneal ed at a tem pera ture of 400 °C for 241Am-Be source of acti vit y 0.2 TBq and neutron yield 4 hours to elim inate inter nal stress. Then the glass of (1.1-1.4)×107 neutrons per sec ond was slowed sam ples were cooled down to room tem pera ture . down, by a Perspex block, to measure the slow neutron Trans par ent and ho mog e nous glass sam ples were ob - at ten u a tion in the in ves ti gated glassy sys tem. The tained. Fi nally glass slab sam ples as shown in fig. (1) transm it ted beam of neutrons was measured under a were pol ished unti l smooth surface s were observe d. good geo met ric con di tion us ing 3He counter as shown in fig. (3). The shielding param eter s of slow neutrons were de duced from the at ten u a tion curves. EX PER I MEN TAL SET-UP

Fast neutr on and total gamma ray RE SULTS AND DIS CUS SION mea sure ments To tal re moval mac ro scopic Measure ments were car ried out for the in ves ti- cross-sec tion of fast neutr ons gated glassy bar ri ers us ing a collimated beam of fast neutrons and gamma rays emit ted from 5 mCi 252Cf The fast neu tron spec tra were measured be hind source with neutron yield of 1.721×107 neutrons per glass barri ers of dif ferent thicknesse s as given in fig. sec ond. Spe cial de tector collimator was used to elim i- (4). It is denoted from such figure that, the measured nate the side scat tered ra di ation to en hance the dis- trans mitted fast neu tron spec tra have nearly the same behav ior be hind all inves ti gated barri ers. It is worth to

Fig ure 3. Sche matic di agram of slow neutr on Fig ure 1. The prepar ed sam ples in bulk form mea sure ments A. A. Saeed, et al.: Neutron Shielding Prop erties of a Borat ed High-Density ... 122 Nuclea r Technol ogy & Ra dia tion Pro tection: Year 2017, Vol. 32, No. 2, pp. 120-126

Fig ure 4. Fast neu tron spec tra be hind dif ferent bar ri ers of the in ves ti gated glass sam ples mention that the neu tron spec tra initially emitted from from 1.4-8 MeV were used to perform the atten u a ti on the irra di a ti on cell does not show any sharp maxim a or rela ti ons of fast neutrons transm it ted through the inves - minim a, and therefore it is quite suitable to be used for ti gated glass barri ers of thickness varying from 0 cm up the de ter mi na tion of the in ves ti gated glass bar ri ers to 6.74 cm. The transm it ted fast neutron flux through cross-sec tions by the transm ission method. The figure glassy barri ers was given as a functi on of barrie r thick- also showed that the flux decrea sed as the glass thick- ness. Figure 5 showed the rela ti on betwe en total re- ness increa sed for the transm it ted fast neutrons. The to - moval mac ro scopic cross-sec tions (SF) of fast neutrons, tal inte gral fluxes for the region of neutron ener gies which were de duced from the atten u a ti on curves, and A. A. Saeed, et al.: Neutron Shielding Proper ties of a Borat ed High-Density .. Nuclea r Technol ogy & Ra dia tion Pro tection: Year 2017, Vol. 32, No. 2, pp. 120-126 123

Fig ure 5. Vari a tion of to tal re moval mac ro scopic Fig ure 6. To tal re moval mac ro scopic cross-sec tions of cross-section of fast neutr ons with Ba con cen tra tion in slow neu trons in glass sam ples glass sam ples the mol per cent age of barium in the glassy barri ers. It proper ti es of slow neutron im proved as the boron con- can be seen that, the value of SF did not show any appre - cen tra tion in creased. cia ble increa se up to 20 mol% of barium concen tra tion, while at higher con cen tra tions an ap pre cia ble in crease To tal lin ear at ten u a tion co ef fi cients in SF was observe d. This could be at tributed to the re- moval of fast neutrons up to 20 mol% barium concen - The ob tained re sults for to tal gamma ray spec tra, tra tion via in elas tic scat ter ing (n, n/g) which has not pri mary in ad di tion to sec ond ary, trans mit ted through provedwas not so ef fecti ve. While for Ba concen tra - dif ferent barri ers of glass media, were given in fig. 7. tions betwe en 20 to 50 mol %, which is the maxi m um Such figure showed also the initi al prim ary gamma concen tra tion of our choice, the incre m ent of Ba fol- spec tra emit ted di rectly from the ir ra di a tion cell. The lows by a higher rem oval macro scopi c cross-secti on for total gamma ray spec tra, transm it ted through dif ferent fast neu trons via in elastic scatter ing pro cess which may bar ri ers of glass media, had an ir reg u lar pat tern in be fol lowed by ra dia ti on capture proces s for slow down shapes and at ten u a tion pro file. How ever, the dis- neutrons with boron nucle i. The half value thickness played spectra showed that, the total gamma flux was (HVL) and relax ati on length (l) for fast neu trons were not de creased reg u larly as the glass bar ri ers in creased. listed in tab. 1. Figure 5 and tab. 1 showed that, the at- Some peaks were ob served at dif fer ent gamma tenu a ti on proper ti es of fast neutron increa sed as the bar- photon ener gy in the spectra behind glass barri ers. ium concen tra tion increa sed up to 50 mol %. Main peak was observe d at photon ener gy 2.3 MeV in all inves ti gated sam ples. This peak was due to g-ray ini tially emit ted from 252Cf source. Another peak was To tal re moval mac ro scopic ob served at photon ener gy of about 6.5 MeV in cross-section of slow neutr ons sam ples with barium concen tra tions 10, 20, 30, and 40 mol %. This peak was due to the in elastic scatter ing The to tal re moval mac ro scopic cross-sec tions of of fast neutrons with bar ium nucle i (n, n/g), which dis- slow neutrons (SS), de duced from the at ten u a tion appeare d at 50 mol % barium concen tra tion; this may curves, were plot ted ver sus bo ron con cen tra tion as be at tributed to the barium concen tra tion, high enough shown in fig. 6. It is clear that, the values of SS in - to ab sorb sec ond ary g-ray at such ener gy. Pronounced creased as the boron concen tra tion i ncreased up to peak was observe d in the gamma spectra at photon 75 mol %. ener gy 4 MeV in sam ples with barium concen tra tions For slow neutrons, the half value thickness 40 and 50 mol %. Such peak may be due to gamma rays (HVL) and relax ati on length (l) were listed in tab. 2. produced from radi a ti ve capture of slow neutrons by The obtai ned result s showed that, the atten u a ti on boron nucle i in glass sam ple.

Ta ble 1. Cal cu lated ra di a tion pa ram e ters of fast neu trons for glass sam ples un der in ves ti ga tion Pa ram e ter Ba = 0 [mol %] Ba = 10 [mol %] Ba = 20 [mol %] Ba = 30 [mol %] Ba = 40 [mol %] Ba = 50 [mol %] HVL [cm] 15.04 14.12 11.75 5.32 4.18 3.84 l [cm–1] 21.69 20.37 16.95 7.68 6.04 5.54

Ta ble 2. Ra di a tion at ten u a tion pa ram e ters of slow neu trons for glass sam ples un der in ves ti ga tion Pa ram e ter B = 25 [mol %] B = 35 [mol %] B = 45 [mol %] B = 55 [mol %] B = 65 [mol %] B = 75 [mol %] HVL [cm] 11.79 9.37 7.28 5.48 4.63 3.62 l [cm–1] 17.01 13.51 10.50 7.91 6.68 5.22 A. A. Saeed, et al.: Neutron Shielding Prop erties of a Borat ed High-Density ... 124 Nuclea r Technol ogy & Ra dia tion Pro tection: Year 2017, Vol. 32, No. 2, pp. 120-126

Figur e 7. Total gamma ray spectra behin d differ ent barri ers

The at ten u a tion re la tions for in te gral flux of to tal balance betwee n the ab sorpti on term and the new pro- gamma rays, (in the ener gy range from 0.407 to duced g-rays term. While an ap pre ciable in crease in mT 7.19 MeV) measured be hind the inves ti gated glass was observe d at higher concen tra tions up to 50 mol %, bar ri ers, were used to de rive the to tal linear at ten u a - which meant that the absorp ti on term excee ded the –1 tion co ef fi cients [mT, cm ] and were plotted as a func - produc ti on term. Strange result was obtai ned at bar- tion of barium concen tra tion, as shown in fig. 8. mT of ium concen tra tion 40 mol %. g-rays showed a very slight increa se with bar ium con- The half value thickness (HVL) and re laxati on centra tion up to 20 mol %. This can be attri b uted to length (l) for to tal gamma rays were listed in tab. 3. A. A. Saeed, et al.: Neutron Shielding Proper ties of a Borat ed High-Density .. Nuclea r Technol ogy & Ra dia tion Pro tection: Year 2017, Vol. 32, No. 2, pp. 120-126 125

Ta ble 3. Ra di a tion pa ram e ters of to tal gamma rays for glass sam ples un der in ves ti ga tion Pa ram e ter Ba = 0 [mol %] Ba = 10 [mol %] Ba = 20 [mol %] Ba = 30 [mol %] Ba = 40 [mol %] Ba = 50 [mol %] HVL [cm] 10.16 12.06 09.55 05.68 12.16 05.05 l [cm–1] 14.66 17.39 13.77 08.20 17.54 07.28

In no va tion and Ap plied Stud ies, 3 (2013), 4, pp. 1079-1085 [4] Saeed, A., et al., Opti cal Proper ties of High Density Bar ium Bo rate Glass for Gamma Ray Shield ing Appli - ca tions, Op ti cal and Quan tum Elec tron, 48 (2016), 1, pp. 3-10 [5] Osman, G., Gamma and Neu tron Shield ing Char ac - ter is tics of Con cretes Con tain ing Dif fer ent Cole man - ite Pro por tions, Nu clear Sci ence and Tech nol ogy, (2012), pp. 41-49 [6] Hossian, M. S., et al., Study of Shield ing Be hav ior of Some Multilayer Shields Con tain ing PB and BX, In- dian Journal of Pure and Applied Physics, 48 (2011), 4, pp. 860-868 Fig ure 8. To tal lin ear at ten u a tion co ef fi cients of g-rays in [7] Ko, W., The Atten ua tion of Neu trons in Bar ite Con - glass sam ples crete, Uni ver si ties Re search Jour nal, 4 (2011), 4, pp. 193-203 CON CLU SION [8] ***, Paul Reuss Neu tron Physics, EDP Sciences, 2008 [9] Vishwanath, P. S., Badiger, N. M., Gamma Ray and Neu - Synthe sis of novel transpar ent glass mater iel tron Shield ing Prop er ties of Some Al loy Ma te ri als, An- was studied regard ing the shielding proper ti es of fast, nals of Nu clear En ergy, 64 (2014), pp. 301-310 slow neutrons, and total gamma rays. Inte gral flux val- [10] Vishwanath, P. S., et al., Com par a tive Stud ies on ues of fast and slow neutrons de creased expo nen ti ally Shielding Proper ties of Some Steel Alloys Using Geant4, MCNP, WinXCOM and Ex per i men tal Re - with in creas ing the bar ium and bo ron con cen tra tion sults, Ra di a tion Phys ics and Chem is try, 106 (2015), re spec tively. The g-ray shielding for such sam ples Jan., pp. 255-260 were effec tive at bar ium concen tra tion exceedsing [11] Sandeep, K., et al., In ves ti ga tion of Struc tural Prop er - 20 mol % up to 50 mol % as an opti on, in which it ties of Bis muth Sili cate Glass System as Gamma Ray agrees with what was obtai ned in our previ ous work Shield ing Ma te ri als, Asian Jour nal of Ap plied Sci - ences, 1 (2013), pp. 99-103 done on the same sam ples for pure gamma emit ter [12] Marzieh, S., et al., Fab ri ca tion and Radiocharacterization [18]. Obtai ned result s for neutrons and gamma rays of Bo ron Car bide and Tung sten In cor po rated Rub ber may be use ful for nu clear re search com mu nity and Shields, In ter na tional Jour nal of In no va tion and Ap plied shielding design of hot cells. Stud ies, 4 (2013), 2, pp. 437-440 [13] Gh. Eid, M. M. et al., Neu tron Shield ing Using Li3BO3/ /Ep oxy Com pos ite, Re searcher, 3 (2011), pp. 85-92 [14] Siqi, Xu, A Novel Ultra-Light Structure for Radi a tion AU THORS' CON TRI BU TIONS Shield ing, M. Sc. the sis, North Carolina State Uni ver - sity, Ralligh, N. C. USA, 2008 The sample prep ara tion was done by A. Saeed. [15] Al A., Ahmed. J. M., Measure ment of Inelas tic Scat- The mate ria l proper ti es work was done by M. M. ter ing Cross-Sec tions For Re ac tor Fast Neu trons El-Okr, A. M. Abou El-azm, Y. H. Elbashar. The ra dia - From Yb174 Using the Time of Flight Tech nique”, Arab Jour nal of Nu clear Sci ences and Ap pli ca tions, tion measure ments and their data anal ysis were car ried 45 (2012), 2, pp. 283-289 out by A. Saeed, R. M. El Shazly, M. N. Hussien [16] Zawisky, M., et al., Neu tron Tomographic In ves ti ga - Comsan, W. A. Kansouh, A. R. El-Sersy. tions of Bo ron-Al loyed Steels, Jour nal of Nu clear Ma te ri als, 327 (2004), 2, pp. 188-193 [17] Abdullah, Y., et al., Prop er ties of Con crete/Bo ron Car - bide as Neutron Shielding Mate ri al s, Jour nal of Nu clear REF ER ENCES and Relate d Technol o gie s, 8 (2011), 2, pp. 15-25 [18] Aly Saeed, R. M., et al., Gamma Ray At ten u a tion in [1] Elmahroug, Y., et al., Cal cu la tion of Fast Neu tron De vel oped Bo rate Glassy Sys tem, Ra di a tion Phys ics Romaval Cross-Sec tion for Dif fer ent Shield ing Ma te - and Chem is try, 102 (2014), Sept., pp. 167-170 ri als, In ter na tional Jour nal of Phys ics and Re search, 3 (2013), 2, pp. 7-16 [2] Kaur, S., Singh, K. J., In ves ti ga tion of Lead Borate Glasses Doped with Aluminium Oxide as Gamma Ray Shield ing Ma te ri als, An nals of Nu clear En ergy, 63 (2014), Jan., pp. 350-354 [3] Amirabadi, E. A., et al., Study of Neu tron and Gamma Recei ved on Octo ber 7, 2016 Ra di a tion Pro tec tive Shield, In ter na tional Jour nal of Accept ed on March 2, 2017 A. A. Saeed, et al.: Neutron Shielding Prop erties of a Borat ed High-Density ... 126 Nuclea r Technol ogy & Ra dia tion Pro tection: Year 2017, Vol. 32, No. 2, pp. 120-126

Ali Abdalah SAID, Raed Mohamed EL [AZLI, Mohamed Mahmud EL-OKR, Ali Mohib Abu EL-AZM, Jahija Hamdi ELBA[AR, Mohamed Nasef Hasan KOMSAN, Vagdi Ahmed KANSUH, Ahmed Reda EL-SERSI

SVOJSTVA STAKLA VISOKE GUSTINE TRETIRANOG BOROM U ZA[TITI OD NEUTRONSKOG ZRA^EWA

Eksperimentalno su odre|ena za{titna svojstva stakla visoke gustine tretiranog borom od neutronskog zra~ewa. Radi karakterizacije atenuacionih svojstava sistema stakla (75-x) B2O3-1Li2O-5MgO-5ZnO-14Na2O-xBaO, u uslovima dobre geometrije merewa, odre|eni su ukupni makroskopski efikasni presek za uklawawe brzih i sporih neutrona i linearni koeficijent slabqewa ukupnog gama zra~ewa, primarnog i sekundarnog. Kako bi se izmerila atenuaciona svojstva brzih i sporih neutrona i ukupnog gama zra~ewa, plo~e razli~itih debqina ispitivanog stakla izlagane su kolimisanom snopu neutrona emitovanih iz izvora 252Cf i 241Am-Be. Rezultati potvr|uju da je staklo sa barijumom i borom pogodno za prakti~nu primenu u oblasti za{tite od zra~ewa.

Kqu~ne re~i: za{titni materijal, brzi neutron, spori neutron, efikasni presek za uklawawe, gama zra~ewe